Participants in the construction industry are constantly challenged to deliver successful projects despite tight budgets, limited manpower, accelerated schedules, and limited or conflicting information. The significant disciplines such as architectural, structural and plumbing and electrical must be coordinated to ensure efficiency.
In the past, traditional building design was largely reliant upon two-dimensional drawings (plans, elevations, sections, etc.). However, modern building techniques include electronic building information modeling (BIM). BIM extends traditional building design beyond two dimensional drawings by providing electronic display of projects in three dimensions. BIM also covers spatial relationships between components and equipment installation, light analysis, geographic information, and quantities and properties of building components.
The BIM concept provides a virtual construction of a facility prior to its actual physical construction, in order to reduce uncertainty, improve safety, and increase efficiency between sub-contractors. Sub-contractors from various disciplines can input critical information into the electronic model before beginning construction, with opportunities to pre-fabricate or pre-assemble some systems off-site. Waste can be minimized on-site and products delivered on a “just-in-time” basis rather than being stock-piled on-site.
Quantities and shared properties of materials can be extracted easily. Project scope work can be isolated and defined. Systems, assemblies and sequences can be shown in a relative scale with the entire facility or group of facilities. BIM also prevents errors by enabling conflict or ‘clash detection’ whereby the computer model visually highlights to the team where parts of the building (e.g., structural frame and building services pipes or ducts) may wrongly intersect.
The BIM concept involves representing a design as combinations of “objects.” The objects are typically undefined, generic or product-specific, solid shapes or void-space (like the shape of a room), that carry their geometry, relations and attributes. BIM design tools allow extraction of different views from a building model including objects for drawing production and other uses. These different views are automatically consistent, being based on a single definition of each object.
For the professionals involved in a construction project, BIM enables a virtual information model to be handed from the design team (architects, surveyors, civil, structural and building services engineers, etc.) to the main contractor and subcontractors and then on to the owner/operator; each professional adds discipline-specific data to the single shared model. This reduces information losses that traditionally occurred when a new team takes ‘ownership’ of the project, and provides more extensive information to owners of complex structures.
Use of the BIM concept extends beyond the planning, design and construction phases of a project, into the building life cycle, including uses in cost management, maintenance management, and facility operation.
Many software programs are available for implementing a BIM concept. For example, Revit is available from Autodesk of San Rafael, Calif. Revit products use “.RVT” files for storing BIM models. Typically, a building model is constructed using 3D wireframe objects to create walls, floors, roofs, structure, windows, doors ductwork, electrical systems and other objects as needed. These 3D objects are generally organized “families” and are saved in appropriate files in a database, and to be later imported into a graphics display routine.
A BIM “model” is typically a database file represented in the various ways which are useful for design work. Such representations can be plans, sections, elevations, legends, and schedules. Because changes to each representation of the database model are made to one central model, changes made in one representation of the model (for example, a plan) are propagated to other representations of the model (for example, elevations). Thus, drawings and schedules are always fully coordinated in terms of the building objects shown in drawings.
Revit is only one of many varieties of BIM software which support an open XML-based IFC standard. This file type makes it possible to standardize workflow from different discipline consultants of a building project.
Despite its advantages, the BIM concept of the prior art lacks the ability to track the real time location, expertise and other attributes of construction workers while they are on-site. “Collisions” of workers, including duplication of effort, attendance and allocation of resources are not integrated into the BIM concept. Applicant has recognized that a need exists to integrate worker tracking into the BIM concept to enable efficient allocation of various skill levels and disciplines of workers, and to identify and isolate problems such as choke points and excess labor force allocation.
Applicant has also realized that no one tracking technology provides the dependability required to efficiently and reliably track and identify construction workers in a “live” building construction project. For example, large moving steel equipment, concrete, construction barriers, walls and high current electric devices such as air handlers and generators present on a live construction site all interfere to some degree with different tracking technologies at different times leading to failure.
Despite their limitations, certain known technologies, when combined in a way described by Applicant, provide a novel solution to the problems of tracking and monitoring workers in a live construction project.
One generally reliable tracking technology is a radio-frequency identification system (“RFID”). The RFID system uses electronic tags attached to the objects to be identified.
The RFID tag stores information electronically in a non-volatile memory. The RFID tag includes a small RF transmitter and receiver. An RFID reader transmits an encoded radio signal to interrogate the tag. The tag receives the message and responds with its identification information. The response generally includes a unique tag serial number, and product-related information such as a stock number, lot or batch number, production date, or other specific information. RFID tags usually contain an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, collecting DC power from the incident reader signal, and other specialized functions and an antenna for receiving and transmitting radio frequency signals.
Another known technology utilized by Applicant is the Global Positioning System or GPS. GPS provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver.
GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of an RS-232 port at 4,800 bit/s speed. Data is actually sent at a much lower rate, which limits the accuracy of the signal. Receivers with internal DGPS receivers can outperform those using external RTCM data.
Many GPS receivers can relay position data using the NMEA 0183 protocol. Although this protocol is officially defined by the National Marine Electronics Association (NMEA), references to this protocol have been compiled from public records, allowing open source tools like “gpsd” to read the protocol. Proprietary protocols also exist, such as the SiRF and MTK protocols. Receivers can interface with other devices using methods including a serial connection, USB, or Bluetooth.
Civilian GPS devices provide latitude and longitude information, but, are not considered sufficiently accurate or continuously available enough (due to the possibility of signal blockage and other factors) to rely on exclusively to transmit highly accurate location information over a wide range of building construction equipment due primarily to interference from concrete and steel structures.
The prior art has attempted several piecemeal solutions using either RFID or GPS, but none have attempted to combine positioning systems with a BIM model or other 3-D construction modeling systems and none have been completely satisfactory.
For example, a known method for attaching an RFID tag to a worker is U.S. Pat. No. 8,191,292 to Cummings, et al. and U.S. Pat. No. 8,193,940 to Cummings, et al. Cummings, et al. disclose a device for displaying a recognition award includes a hard hat and an RFID tag located in a detachable holder on the hard hat. The device is used to provide a hands free way to position an RFID tag at an easily recognizable location on the construction worker. But, Cummings, et al. do not disclose a way to integrate the RFID tag with a BIM model.
International Patent Publication No. WO 2006/013587 to Di Floriano describes a system including a plurality of sensors in a targeted area tracking a plurality of people carrying RFID devices. Di Floriano lacks the means or necessary systems to precisely track location, having only the ability to ascertain if a person carrying an RFID device is inside the targeted area.
U.S. Patent Publication No. 2003/0013146 to Werb discloses a real-time locating system using a hybrid tag device having a dedicated location position system transmitter and a beacon transmitter. However, Werb does not disclose a way to input location information into a BIM system or to compensate for problems caused by obstructions on a construction site which interfere with the locating system.
U.S. Patent Publication No. 2008/0312946 to Valentine, et al. proposes location based services including real-time tracking and information management for trade show events. Valentine, et al. do not describe a system for initiating tracking information with a construction BIM or a redundant position system which compensates for obstructions.
U.S. Patent Publication No. 2008/0195434 to Broughton discloses a system for managing construction information based on a graphic model. Parameters such as installation status, cost status, and delivery times are associated in a database with a component in the graphical model. RFID tags are used to analyze the location of the object and its status as “installed” or “uninstalled.” However, Broughton does not disclose a way to integrate location information of personnel or construction workers into a BIM model nor does it provide a way to track or avoid constantly moving items (like workers) and compensate for building construction obstructions.
Various embodiments disclosed address the need for worker location system for building construction projects which allows integration of personnel location information from synchronized RFID and GPS location systems and a coordinated upload of location information into a BIM format for display. Other disclosed embodiments provide synchronizing of location information to greatly improve the reliability of GPS information with RFID information.